


If This Be Error

by Elspethdixon, Seanchai



Category: Marvel, Marvel 616
Genre: Alternate Universe - World War II, Gen, Pre-Slash, Teen Sidekick Bucky Barnes, The Blitz
Language: English
Status: In-Progress
Published: 2017-10-02
Updated: 2017-10-30
Packaged: 2019-01-08 01:30:22
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 15,280
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/12244500
Author URL: https://archiveofourown.org/users/Elspethdixon/pseuds/Elspethdixon, https://archiveofourown.org/users/Seanchai/pseuds/Seanchai
Summary: As the winter of 1940-1941 draws to a close, American military asset Steve Rogers is sent to London in order to make a show of helping the British war effort (and acquire in-the-field training in the process).  Engineer Tony Stark is there as well, aiding the British government in breaking enigma codes, and using his 'Iron Man' armor to fight his own secret battle against the German Blitz.  Finally able to openly fight the enemies he clandestinely faced back in the states, Steve is determined to do his all to defeat Germany.  Tony is determined never to let his technology be used by an Axis power again.  Bucky is determined to keep Steve from getting killed. And somewhere deep within Germany, mad scientist Heinrich Zemo is determined to summon monsters from another dimension to fight for Hitler's cause.





	1. Chapter 1

**Author's Note:**

> This fic is based on a combination of standard 616 canon (time-shifted to the 1940s) and some elements of Golden Age Captain America canon (Betsy Ross appears instead of Peggy Carter, who was a later Silver Age addition). Our working title of “Captain America & Iron Man vs. the Nazi Mummies” had to be discarded, because there are no mummies nor indeed anything remotely resembling mummies anywhere in the fic. Maybe next time.

The warehouses in the East End were burning again – he could smell the chemical tang in the smoke, underneath the acrid smell of explosives and the heavy scent of a gas leak from somewhere uncomfortably close. Fire itself made a noise, Tony had learned that in China, but he couldn’t hear it over the drone of airplane engines and the ear-splitting rattle of the anti-aircraft gun on the next block.

Nearly two months in London, and he still hadn’t gotten used to how loud it was.

The hotel that took up most of the block was already burning, the front façade and half the roof missing and the top three floors caved in. A building like that would have a big basement, and since the closest subway station had been damaged in the last raid, it would be packed with people.

He cut his jet boots a good six feet above the ground and let himself fall the rest of the way, just to be safe. Tony had replaced the original rocket boots with a combination of miniaturized jet engines and vectored thrust when he’d built his second suit, but there was still enough heat and flame to be deadly if he landed too close to that gas leak.

Close up, it was obvious that the hotel was no longer structurally sound. He was going to have to be careful moving the rubble.

Tony activated the armor’s cooling fans and strode forward, chunks of plaster crunching under his boots. That partially collapsed section of wall and the fallen ceiling beam resting across it were the only things holding up the weight of the upper floors; he couldn’t move them, or anything that was holding them in place. If the entrance to the cellars was under any of that, the people inside were – he’d find a way to get them out.

Inside the building the air was thick with smoke and almost too hot to breathe, and Tony thought briefly and uselessly of Gene’s ice ring. His air filters had already failed, and his armor’s internal oxygen supply was exhausted. It didn’t matter; it wasn’t that hard to breathe in here, not yet.

The grand staircase to the second floor had collapsed into a heap of smoldering rubble, partially blocking what had to be the cellar entrance. Someone on the inside had pulled the door inward, and as Tony came closer, he could hear the sound of panicked voices, and the high pitched wailing of a small child.

“Hush,” a woman’s voice said firmly. “Up you go.”

A small, round face appeared in the opening, belonging to a child of indeterminate gender. It saw Tony and shrieked.

A heavy overcoat had been laid across the top of the pile of rubble, enough to offer some protection against the heat, but it didn’t stretch all the way to the floor. The little boy – girl? – stared at Tony with huge eyes, frozen in place, unable to back away without falling into the cellar.

“It’s okay,” Tony tried. “I’m going to get you out of here.”

“Mommy!” the child wailed. “Mommy, there’s a robot!”

He should have listened to Happy and painted his armor, but the dull grey was harder to see at night, and kept the German fighters from firing on him.

“I’m a nice robot,” he offered, painfully aware of the weight of the upper stories hanging over their heads. The ceiling beams were heavy, and would take hours to burn through, but the heat would already be weakening them. They would crack and splinter long before they turned into char.

“Andrew, if you don’t climb down and run outside like a good boy, I will give you such a smack.”

The little boy inched forward, his face screwed up as if he were about to cry, and Tony snatched him off the heap of rubble before he could fall off the coat and onto the burning remains of the staircase. He set him on the floor, and looked up to find that a little girl had already taken his place atop the rubble. She looked a year or two older than the boy, and was clutching a stuffed giraffe.

She gave him a wary look, but kept quiet as he lifted her down, then immediately latched on to the little boy.

Three more children followed, and then Tony looked up, ready for the next one, to find himself staring at the blood-covered face of a woman.

“There are nearly fifty more people down here,” she said. “At least ten more are children, but they’re all too big to fit through this gap. We have to move some of the rubble out of the way.”

“I’ll do it,” he said. “You’ll burn your hands. Is anyone hurt?”

“Mrs. Shores has a broken arm, and she’s lost consciousness. I think her husband is dead. They were the closest to the door.” She didn’t mention herself, despite the vicious gash that stretched from her hairline nearly to her jaw.

Tony didn’t mention it either. He just started shifting rubble, careful not to destabilize the pile.

The last collapsing building he’d gone into had been full of dead bodies, and there had been the shattered remains of someone impossible to identify on the street outside. One death and one broken arm was a hell of a lot better than he’d expected.

His chest started to ache halfway through shifting the pile, and the armor’s cooling fans were wheezing loudly enough that he could hear them even over the roar of the fire and the sound of engines and gunfire overhead. English fighter planes, this time; the Merlin engine had a different pitch than the Daimlers and Jumos that powered Messerschmitts, Junkers, and Heinkels.

Junkers and Heinkels with Stark Industries-inspired bomb sites, thanks to dear old dad selling SI’s designs to anyone who could pay for most of the thirties.

Without the armor’s gauntlets, his hands would have been a mass of burns by now, past the point of uselessness. As it was, the metal was starting to get uncomfortably hot.

“Right. I think that’s done it,” the woman announced. She coughed, holding the end of her sleeve over her face, then went on, her voice hoarse. “We’ll pass Mrs. Shores up to you first.”

Tony gave her his most charming smile; the helmet would hide it, but those kind of things came through in the voice. “If I weren’t wearing this metal helmet, I could kiss you.” He’d expected frightened, panicking people, or shell-shocked casualties too stunned by disaster to be any help to him.

She touched the back of her hand to her forehead, pushing back hair sticky with blood, then winced. Whatever had cut open her face had also raised a bruised lump the size of a silver dollar over her left eye, and it was already starting to swell shut. “Not with the way I probably look,” she said.

“I like my women covered in soot and plaster dust,” Tony assured her. Then the armor’s low power warning sounded.

No more time for flirting with strangers who probably needed medical attention more than they needed attention from Tony Stark. He tore one of the sleeves off the now-smoldering overcoat and wrapped it around his gauntlets, insulation between the hot metal and the next person he touched. “Pass Mrs. Shores up.”

They had rigged up a crude stretcher using parts of a folding chair and several blankets. The woman on it was old enough to be Tony’s mother, and her left arm was a bloody, swollen mess. She didn’t even twitch when he hauled the stretcher up and over the remains of the rubble, even when a shower of sparks from the ceiling fell onto her dress and Tony had to clumsily pat them out.

He should have installed some kind of fire-fighting upgrade weeks ago. It was ridiculous to be putting out sparks with his hands, not to mention incredibly inefficient.

“Who the hell are you, and what are you doing to that woman?”

Tony whirled, automatically bringing up one hand – the repulsors he’d designed as flight stabilizers could take care of any human attacker as easily as they could a German plane – then forced himself to relax when he saw the distinctive shape of a civil defence helmet. “Trying to get her out of here.” It was a cliché, but- “I’m here to help.”

The air warden stared at him for a moment, then shook his head. “The little girl said there was a robot. I thought she was hysterical.” His Cockney accent was thick enough that he sounded almost like he was speaking a foreign language, all swallowed consonants and sharp vowels. “What are you?”

Almost out of power, according to the buzzer sounding annoyingly in his ear. “There are more people down there, and the ceiling’s about fifteen minutes away from caving in. You can gape at me later.” He held up one hand, and fired the repulsor at one-sixth power for a fraction of a second, just enough to shred his makeshift woolen ‘glove.’ “I even do tricks.”

The air warden called him an uncomplimentary name, but more people were arriving now, hustling bombing victims out of the building and throwing wet blankets down across the partially cleared entrance to cellar to make it easier for people to crawl out. Tony waiting just long enough to see the woman with the injured face emerge from the rubble, then left.

There was more he could have done – there was always more – but he wouldn’t be able to help anybody if he ran out of power and passed out.

He made it most of the way back to Bletchley before the armor’s power reserves ran dry and he had to switch to the nearly-empty battery powering his chest device. By the time he landed, and was climbing back through the window of his supposedly-secure room, the armor tucked back inside his briefcase, Tony could almost feel the shards of shrapnel moving around inside his chest.

He plugged himself into the electrical outlet by the nightstand and collapsed backward onto the bed, too exhausted to care how he was going to hide the blisters on his hands tomorrow.

His window faced southeast. Outside it, he could see London burning on the horizon.

***

He’d read the worn and creased copy of LIFE three times in two days since he’d traded half of Bucky’s bubblegum and a pack of the cigarettes that he didn’t smoke for it, but the full-page picture of Rita Hayworth on page seventeen was still worth a few minutes attention. Lieutenant Ross wore her hair the same way.

Steve stared at the photo, imagining how the Lieutenant would look in the same flower-patterned sundress, and how the last conversation they’d had out of uniform could have gone if he’d been less of an all-around idiot.

He’d have started by not tripping over his own feet and spilling coffee on her, then would have actually asked her out dancing instead of just hinting that “a lot of the guys” were going out to have a night on the town, and that he was thinking about going as well, but it wasn’t any good going by himself and what was she planning on doing this weekend? Then, when she smiled at him and told him that he was a nice kid who was going to make some girl very happy someday, he would have had something charming and witty to say in return, instead of just staring at the table while his ears went red and he wished for the ground to open up and swallow him.

He’d hoped that taking down those saboteurs together would make her think differently of him, stop seeing him as some naïve, clumsy kid and talking to him as if he were her little brother. It didn’t seem to have made any difference at all.

A dull, repetitive thumping sound from the bunk above him dragged Steve out of his haze of remembered embarrassment. Bucky was tapping one foot against the wall, over and over.

“I thought we agreed we were taking turns in the top bunk.” Steve addressed the metal bedframe over his head, not really expecting an answer.

“We did.”

“Then how come you’ve been in it the entire trip, Sport?”

“Safety reasons.” Bucky said this as if it were self-evident.

“Safety reasons.”

“Yeah.” Bucky’s head appeared over the side of the bunk. Even upside-down, his earnestly sincere expression was obviously fake. “This thing,” he smacked the bed frame with a fist, “looks pretty flimsy. You’re about the size of a gorilla, so if I let you have the top bunk, it might collapse under your weight and crush me in my sleep.”

Steve closed the magazine and tossed it aside, tucking his arm behind his head and leaning back as if Bucky weren’t hanging in his personal space like a particularly un-intimidating gargoyle. “I suppose it’s only fair to humor children.”

Bucky glared at him, a sulky expression that made him look ridiculously young. The uniform blouse flapping unbuttoned at his throat didn’t do anything to remedy that. He _was_ ridiculously young to be wearing it, enough so that Steve still felt guilty for allowing himself to be sworn to silence over Bucky’s actual age, and the fact that he’d lied about it in order to enlist. “Shut up. I’m not a kid.”

“Whatever you say, Champ.”

“If you don’t stop calling me that, I’m going to kill you in your sleep.”

Steve grinned at him. “You and what army?” He didn’t need to point out that Bucky was about five foot five inches tall and weighed a hundred and ten pounds dripping wet. Even before the Army’s experiments, Steve would have towered over him.

Bucky’s eyes narrowed. “I’ll tell Lieutenant Ross that you dream about her.” He raised his eyebrows and put on an expression that was probably supposed to look like lovelorn sorrow, or maybe like desperate passion. “Oh, Betsy!” he gasped, in a falsetto voice that didn’t sound anything like Steve’s. “Oh!”

“Shut up!” Steve snapped.

“I sleep two feet away from you,” Bucky said. “I can _hear_ you.”

“There’s nothing to hear.” His ears were turning red, Steve knew. Damnit, now that Bucky knew he could get to Steve with this topic, he would never, ever drop it. “It’s inappropriate to talk about our commanding officer that way,” he tried.

“I’m not the one who’s sweet on her.”

There was really no good way to answer that. If he denied it, Bucky would smugly insist that he was lying, and if he admitted that he had, in fact, had hopes that Betsy Ross would return his interest, Bucky would badger him into admitting that she’d shot him down, and then unhelpfully ‘commiserate’ with Steve about that the rest of the way to England.

Steve chose the better part of valor and changed the subject completely. “Doesn’t hanging upside-down like that make you feel sick?” he asked.

“Nope,” Bucky said cheerfully.

Of course it didn’t. Steve picked up the magazine again and tried to summon up interest in an article he’d already read three times. He ought to be enjoying all this enforced downtime while he could; once they got to England, he’d be busy fighting Nazis. Not just Nazi sympathizers, spies, or saboteurs, but actual trained soldiers, as part of the actual war.

Was it hard, to kill people? People had died as a result of his covert work in the States, but only one had been at Steve’s hands. He had hit a Nazi saboteur with his shield just as the man was in the act of shooting at Bucky, sending the shot wild, and the weight and angle of the impact had broken the saboteur’s neck. That had been at least partially accidental, and since the result was a live Bucky instead of a dead Bucky, he couldn’t bring himself to regret it. He’d dreamed about it afterward, but those dreams had all involved his hesitating or failing and Bucky dying, not the fact that he had blood on his hands. 

The other deaths had been cleaner. That crazy magician who’d tried to sabotage the defense plant had blown himself up when Bucky had interrupted his spell, and Lt. Colonel Thomas had shot himself when Steve had exposed him as a German spy; he hadn’t actually killed either of them. It wouldn’t be like that in Europe.*

Training dummies didn’t bleed or make any noise when you bayoneted them. Men would do both. They shot back, too.

He should have found some way to keep Bucky from coming.

“How much longer until Portsmouth?”

“Three more days, if we don’t run into any bad weather.”

“Great.” Bucky’s face vanished, and the top bunk creaked as he flung himself onto his back. “I bet London’s full of Nazi spies. It’s a good thing you’ll have my help.”

“They’ll probably send me to France. Or Belgium or Norway, maybe. Wherever the British government thinks I’d be most useful.”

“You mean ‘we.’” Bucky’s voice had that stubborn, almost-scolding note it got when he was determined not to be left out.

He _really_ should have found a way to leave him in New York.

“No,” Steve said, “I mean ‘I.’ You’re staying in London with Lieutenant Ross.”

“Come on, I’m your partner.” 

Bucky sounded offended, and even slightly hurt, but Nazi bullets would damage a lot more than just his feelings. “You were my partner,” Steve corrected him. “Then you enlisted.”

“So I could keep on being your partner. Betsy knows who we really are; she’s not going to make me hang around carrying bags and delivering messages for her.”

“Wanna bet?” Knowing who ‘Private Rogers’ really was had certainly not kept Betsy from giving Steve various fetch and carry duties appropriate to his public rank. 

The mattress above him creaked again as Bucky moved, and a hand appeared around the edge of the top bunk, one finger stabbing accusingly in Steve’s general direction. “That magician guy would have turned you into a bunny rabbit and kept you in his hat if I hadn’t been along.”

“And I’m grateful, but you’re still going to have to do what the brass tell you.”

“Like you do?”

Technically Bucky had him there, but Steve wasn’t about to concede defeat. “Private First Class isn’t my real rank.”

“What is it, then?”

“I don’t know, actually.” No one had ever been clear on that, or on what chain of command he actually belonged to. Funny, when you thought about it; working under the British intelligence service was going to be the first time Steve knew exactly who he answered to and in what order. “I guess I’ll find out when we get there.”

There was silence for a long moment, but Steve knew better than to conclude that he’d won the argument. They’d be revisiting the topic again when they reached London, probably repeatedly. He could let it lie for the moment, though. Betsy, he was sure, would have his back on this. She still treated Steve like some kind of kid brother half the time, and he was twenty-one; Bucky, whose real age she knew perfectly well, was not going to be able to get her to treat him like an adult no matter how much pleading he did.

Just at the moment that the silence had stretched long enough for Steve to resume re-reading his magazine, Bucky spoke up again. “I wonder what the girls are like in England.”

“Too old for you.”

*See “ _Captain America vs. the Mad Magician_ ” and “ _Captain America and the Secret Spy_ ” for Cap and Bucky’s previous adventures.

***

“What the hell did you _do_ , boss?” Happy poked one fingertip gently at Tony’s blistered palm, tightening his grip on Tony’s wrist when he automatically tried to pull away.

“It’s not as bad as it looks.” Tony forced himself to relax and let his fingers uncurl; he needed them bandaged and hopefully less noticeable before he went down to Huts Six and Eight to play with his baby some more. With a layer of fabric over them, he could explain the injuries away as an electrical accident. Or maybe a welding accident – everyone knew he worked on his own mechanical projects in his spare time.

Happy pawed through the first aid kit he’d brought until he found a tube of burn cream, then began to silently apply it to Tony’s fingers and palms. If Pepper were here, she would be lecturing Tony at length until he knew exactly what kind of idiot he’d been, complete with exasperated little sighs and a slightly firmer than necessary touch on his injuries just to make her point. Somehow, Happy’s total lack of recriminations made him feel even worse than Pepper’s worried scolding would have. 

He’d braced himself for pain, but the ointment actually felt soothing against the hot throbbing in his fingers. It wasn’t until Happy started to wrap bandaging around the worst of the burns that it really started to hurt. He managed not to flinch or try and jerk his hand away this time, but it must have shown in his face, because Happy’s hands stilled for a moment, a strip of gauze hanging limply from one of them.

“You shoulda at least tried to bandage them or something before you went to bed,” he said quietly. “Don’t they hurt?”

Tony shrugged. “I’ve had worse.” It was the understatement of the year; his chest still hurt when he breathed in too deeply or moved too sharply, and hopefully he wouldn’t be hauling any heavy machine parts around today, or his hands might not be the first thing to give out. 

He’d cut the timing of his recharge too finely. It always took a couple of days to get back to a hundred percent again when that happened.

Happy snorted. “So have I, but when I got busted up in the boxing ring, I quit boxing.”

As hints went, it wasn’t a very subtle one, but that was Happy for you. “Have you heard anything from Pepper this week?” Tony asked, not bothering to be subtle in return. Happy’s eternal puppydog crush on Tony’s secretary was always a good way to change the topic. “I think she’s still giving me the cold shoulder. All I get are stock reports and wires about business contracts.”

Happy’s face went a little softer, the way it always did when he talked about Pepper. “A gentleman doesn’t kiss and tell.”

“Oh, so it’s like that. I had no idea things were going so well.”

Happy’s mournful-looking expression didn’t change – Tony had never seen him look anything other than vaguely downcast, except when he was laughing at something – but his ears turned pink. Pushing the subject of his relationship with Pepper any further would only embarrass Happy, so Tony let the subject drop. It had done the job of distracting Happy from his injuries, and that was the important part.

Happy taped the final corner of gauze in place, and Tony flexed his fingers, testing the amount of give in the bandage. He still had enough ease of movement to type, or operate a cryptologic bombe, even his more complicated, improved version. The bandages would get in the way if he tried to do any fine machine work, but it was nothing he couldn’t work around. They didn’t cover his entire hand, just the upper part of both his palms and three of the fingers on his left hand. The two burned fingers on his right hand were just red and painful, not raw and blistered like everything else, and Happy had left them open to the air.

If he folded his cuffs down and tried to keep his hands out of sight, maybe nobody would notice all of it. It was a shame he didn’t have the reputation for eccentricity that some of his colleagues did, or he could have gone in with oven mitts on his hands without anyone raising an eyebrow.

“There’s not much to tell even if I weren’t a gentleman. Not with the spooks reading our mail.”

“Believe me, I know,” Tony muttered. Having unknown eyes pour over every letter and telegram he exchanged with his assistant-slash-secretary-slash-second in command or anyone else at Stark Industries was a constant stumbling block to his attempts to run his company, or at least try to not completely ignore it. He’d arranged to have some of his business correspondence sent via the front desk at the London Savoy, but doing so too often would get in trouble, and it wasn’t worth bending the rules for personal letters.

‘Station X’ was the site of some of the most top secret military intelligence work in Great Britain, possibly in the entire world at the moment, if you didn’t count Reed and Bruce’s nuclear program - it had to be a nuclear program; what else would the US government have the best physicists in the world secretly working on* - or whatever warped things the Nazis were doing. It only made sense that everyone who worked there would have their comings and goings and their communication with the outside world monitored. Normally, Tony would have metaphorically thumbed his nose at the whole thing and just written all his mail in code, but under the circumstances… The US government might have the best physicists in the world working for them, but Bletchley Park had some of the world’s best cryptographers, working day in and day out on some of the most sophisticated encryptions ever invented.

He settled for trying to make sure that each week’s outgoing mail included at least one letter to a former and hopefully future lover, using the raciest language possible. He might as well make the censors’ jobs entertaining. After nearly two months, though, he was running out of exes, or at least out of females ones.

Happy was frowning at him again, and Tony realized that he had been sitting staring off into space for… he wasn’t sure how long, actually. For a moment, he contemplated going back to bed; now that he’d finished his work on the improved cryptologic bomb and sent the plans for the construction of additional ones back to SI, there wasn’t much he could do that the best of the cryptographers here couldn’t. And his armor’s gauntlets needed to be repaired, and the latest engine test results for SI’s turbojet project were still waiting inside his briefcase to be looked over, and-

“Are you sure you’re okay, boss? You look,” Happy hesitated for a moment, “tired.”

‘Tired’ was presumably a diplomatic way to say ‘like hell.’

“That’s because I got about two and a half hours of sleep last night,” Tony said, more sharply than he’d meant to. “Sorry,” he apologized. “Thanks for the help.” He reached up to rub at his face, then stopped, remembering the bandages. It was a good thing he’d shaved before calling Happy in here, even though it had been an exercise in misery; he probably needed to keep them dry.

“It’s what I’m here for.”

“Thanks anyway.” Tony managed to dredge up a smile from somewhere. Happy had volunteered to accompany him to England, in spite of the wolf packs of German U-boats that infested the North Atlantic and the bombs that fell on London almost every night. He’d been hovering over Tony ever since China, as if he thought that the same thing would happen all over again as soon as Tony went anywhere on his own, and that only his presence could prevent it.

If he’d been there in China, the Japanese would have killed him. They might not even have bothered to make Tony watch.

He stood up and tugged his cuffs down as far as they would go, managing to cover about a half-inch worth of bandage. It would have to be enough. He had more important things to do than sit around feeling sorry for himself.

If Dane or Alan asked, he’d say he’d been trying to work on something while drunk. They would probably believe it. Dane thought he was a dilettante, and Alan was used to him begging out of early morning fitness runs by pleading a hangover. Most of the others probably wouldn’t ask; half his fellow code-breakers were still in awe of the fact that Tony actually possessed a social life, as well as the ability to speak to real, live women about something other than mathematics.

The armor was a self-indulgent distraction, he reminded himself. The enigma transmissions were what he was really here for.

*Find out what Reed Richards is working on in “ _Mr. Fantastic and the Monster of Los Alamos_.”

***

Steve and Bucky, it turned out, were not the only covert things on this mission.

“Do you think they would waste Captain America on guarding an ordinary lend-lease shipment?” Lieutenant Ross had asked. And then, when Steve had said that he’d been pretty sure the shipment was just an excuse to get him to England without making overt American participation in the war obvious, she’d smiled indulgently at him and said, “Do you think Washington would go to all this trouble just to get you to England? You’re not _that_ important, Private Rogers.”

Behind her back, Bucky had stuck his tongue out at her, while Steve struggled not to tip the lieutenant off and earn Bucky KP duty by glaring at him too obviously. She had had a point.

The ‘lend-lease shipment’ they’d been escorting was not the usual load of surplus machine guns, rifles, and mortars, some of them nearly old enough to be leftovers from the Great War. Hidden amongst them were state of the art torpedo and artillery prototypes from Stark Industries.

In light of that, the crowd of British army and navy officers that now surrounded the ship’s gangplank made sense. At least three were high ranking officers, each accompanied by aides and with a string of subordinates trailing along behind them. The ship’s captain and Lieutenant Ross were talking with them, after an exchange of salutes all around, while Steve and Bucky stood by the first of the off-loaded torpedoes and tried to look imposing.

“I must say, I’m surprised Washington shipped these with so little in the way of guards,” one of the army officers was saying.

Betsy gave him a bland smile. “I follow my orders, Colonel. I’m sure they had their reasons.”

“Yeah,” Bucky muttered. “They were sending us.”

Steve kicked Bucky in the ankle, then went back to standing at attention.

He had learned in basic training how to stand in formation and look as if he was paying attention while tuning out whatever lecture on the ways in which he was a disgrace to the army Sergeant Duffy was delivering. He did the same thing now, tuning out the conversation around him and focusing instead on the way the light from the water rippled across the ship’s hull, on the smudge of smoke visible on the horizon when he looked inland, its edges fading into the grey cloud cover.

It was colder here than it had been when they’d left New York, or maybe it only felt that way because of the wind coming in off the harbor.

The shipyards would make a good sketch, all grey superstructures and hulls against grey water and a mostly grey sky. The Navy Yard at home was close enough to the city that the skyscrapers loomed over it from across the river; here, the ships stood out against the horizon, undiminished by competition.

Someone was approaching. Steve’s attention snapped back into focus at the sound of footsteps, and he saw Lieutenant Ross escorting a woman in a British uniform toward him. “Major Falsworth, this is my escort, Private First Class Rogers and Private Barnes.” Betsy met Steve’s gaze, her eyes moving meaningfully from him to Major Falsworth. This was his contact, then.

She was stunning. Tall, like Betsy, enough so that even in the ugly flats that must have been standard service issue, she didn’t have to tilt her head back to meet Steve’s eyes. Her blonde hair was pulled back and up in a severe hairstyle that probably involved lots of bobby pins, leaving the strong bones of her face clearly visible.

“Is that so?” she said. “I expected someone a little more experienced.”

“Private Rogers is extremely capable, Ma’am.”

Steve felt his face heat at the praise, then heat further as Major Falsworth continued to stare at him appraisingly.

“I’ll have to take your word for that, Lieutenant.” She pronounced it ‘left-tenant.’ “How did you find the trip over, Rogers?”

Steve’s mind went blank, the same way it had the first few times he’d tried to speak to Lieutenant Ross. “I… uh… fine. Ma’am. It was fine.” He sounded like an idiot, exactly like the naïve screw up ‘Private Rogers’ was supposed to be and not at all like Captain America ought to sound. Which would have been fine, except that costume or no costume, he was supposed to be Captain America right now. And Major Falsworth looked even less impressed than she had a moment ago.

Lieutenant Ross’s fondly amused smile just made Steve want to sink further into the ground.

Falsworth’s gaze shifted to Bucky, and Steve felt a ridiculous pang at the loss of her attention even as he inwardly sighed in relief. “And you, Barnes? This is your first assignment, I imagine.”

“Oh, no, Ma’am,” Bucky said brightly. “I’ve been on duty with Private Rogers for several months.” It technically true, if you interpreted ‘on duty’ very, very liberally.

Falsworth turned to Lieutenant Ross, her face incredulous. “You can’t be serious,” she said in an undertone. “A pair of fresh recruits, one of them not even old enough to shave? That’s who I’m supposed to take back to headquarters with me?”

“I can promise you, Major, Private Rogers is highly trained and very good at what he does.”

“And the other one?”

“I’ll brief you on that later. The full details are classified.”

“Is he very good at what he does, too?”

“He’s very enthusiastic.”

Bucky’s grin was somewhere between shit-eating and frankly evil. Steve considered kicking him again.

Falsworth straightened into something that was not quite attention, and Steve automatically followed her line of sight.

One of the Naval officers was approaching them, accompanied by a man in civilian clothing. The officer was tall and thin, with a craggy, aristocratic face and pale eyes, and an admiral’s golden insignia on his collar tabs. He wore a Victoria Cross pinned to the breast of his uniform jacket. Beside him, the civilian’s generously cut suit looked flashy, and his hair – which was just a little on the long side – unkempt.

Double breasted suit jackets were discouraged in England, weren’t they? Steve vaguely remembered something in the little booklet explaining rationing that he’d been given mentioning that.

“Admiral Hunter, Sir.” Lieutenant Ross saluted smartly. “Would you care to inspect the shipment?”

“With pleasure, Lieutenant. Anthony, care to take a look?”

The civilian was already moving forward, reaching out to run his fingertips over the side of nearest torpedo. It almost looked like he was petting it. “These are state of the art, Admiral. The depth keeping mechanism and magnetic influence exploder are years ahead of the German and Japanese designs, as well as any other ordinance our navy carries.” His voice was very American, the kind of educated, East Coast accent Steve associated with Washington politicians and townhouses on the Upper East Side. “You.” He nodded at Steve. “Come help me get this off.” It was too casual to be an order, but his self-assured tone made it obvious that he expected to be obeyed.

Steve glanced at Lieutenant Ross for confirmation, then stepped forward and helped Anthony the maybe-civilian remove the head of the torpedo.

The torpedo was nearly two feet across, almost as big as his shield, and it took all of Steve’s strength to coax the solid cap of metal to come free, even with the other man’s assistance. How had he planned to get it off if help hadn’t been available?

“Thanks,” Anthony said, and flashed him a quick grin that made Steve’s stomach flutter with sudden, completely inappropriate attraction. His teeth were very white, his eyes a startlingly pale blue-grey against black hair and brows, and the curve of his lower lip was—

Not something Steve should be noticing. He had enough trouble with women without risking opening himself up to charges of conduct unbecoming or arrest for sodomy. At least being attracted to women, as intimidating as flirting with them or even talking to them sometimes was, was acceptable, legal, normal.

“The powerplant is a combination wet heater combustion and steam turbine,” Anthony was saying, “and it has a range of anywhere between four thousand and nine-thousand yards, depending on the speed it’s running at. We’re still having trouble with the contact exploder, but this newest model’s almost completely eliminated the problem, and we don’t have any of the gyro problems the—“ he broke off abruptly, and smiled at the Admiral, shrugging one shoulder. “Well, anyway, we don’t have any gyro problems. You don’t have to worry about this baby running circular.”

The admiral raised his eyebrows. “You don’t need to sell them to us. We’ve already bought them.”

Anthony stared at him blankly for a moment, then smiled that movie-star smile again. There was something vaguely familiar about it, but Steve couldn’t quite place it. “Sorry. Occupational hazard.” He patted the side of the torpedo, and said, “This one looks good. Let’s open a couple of these shipping crates and check out a few more. Make sure everything made it okay.”

By the fifth torpedo, Steve was re-evaluating his estimation of the man’s attractiveness. Over two hours of being blithely ordered around by a civilian made up for any amount of good looks. It was nearly sunset, the lids of the crates and heads of the torpedoes were heavy even by his standards, and he hadn’t had a chance to sit down or eat since they’d gotten off the boat. Surely this could have waited until tomorrow morning.

They’d accumulated an audience along the way, which meant that Steve’s every move took place under the eyes of half a dozen highly ranked British military officials, as well as Major Falsworth. ‘Hold this, Rogers. And this, and this, and this. And make sure to look like a regular joe for the Navy and Army brass without doing anything clumsy that would make the intelligence officers lose faith in you.’

“Okay,” the other man finally said, after Steve had levered the lid back onto the third shipping crate. “That’s probably enough for now. Most of the shipment looks like it’s in order, and nothing seems damaged. I think that last one might be defective, though.” His eyes went to Steve. “Mark that crate and I’ll take a closer look at it tomorrow. I can probably fix it.”

“That’s good to hear.” Lieutenant Ross didn’t sound all that impressed with Mr. Torpedo either. It made Steve feel pettily vindicated.

One of the army officers eyed Anthony skeptically, probably taking in the ostentatiously well-cut suit and distinctly non-military hair. “And you are?”

Falsworth stepped forward. “Sirs, allow me to introduce Anthony Stark, of Stark Industries. He worked with His Majesty’s government to arrange this shipment.”

Tony Stark? Anthony the Civilian was Tony Stark? No wonder he’d looked familiar.

Tony Stark was a minor celebrity in New York: the son and heir of millionaire businessman Howard Stark, who’d taken over the company after his father’s sudden death last year. He was infamous for his fast cars, his parties, and for dating actresses and Broadway chorus girls. He was supposed to be some kind of engineering genius as well, but the papers and newsreels were less interested in that. Steve had always thought of geniuses as reclusive scientists, like Dr. Erskine, not attractive young men in flashy clothes with perfectly styled hair.

“Pleased to make your acquaintance, gentlemen,” Tony Stark said, and of course that smile was familiar. Steve had seen it in gossip rags and newsreels and on the front page of the Daily Bugle. He’d seen Stark smiling that smile for the camera with a silk-draped and fur coat wearing starlette on each arm. “I’m delighted that His Majesty was smart enough to buy his munitions from Stark Industries.”

The papers had always made him sound like a charming son of a bitch. Obviously they weren’t exaggerating by as much as the Bugle usually did.

Everyone exchanged pleasant formalities for a while, while Steve, Bucky, and Lieutenant Ross stood there quietly being too low-ranking and unimportant to speak to, or even really notice. By the time someone finally got around to remembering that the Americans had just disembarked from a transatlantic ocean voyage and needed to be fed and billeted somewhere, the long line across the horizon where the sky and water met was starting to turn orange and pink.

Major Falsworth took charge of them with an air of authority that confirmed Steve’s suspicions that she was more important in British Intelligence than her rank indicated. There would probably be briefings to sit through before he and Bucky finally got to eat, but at least he’d finally get to speak, even if it was as ‘Captain America.’

There was an exchange of salutes all around, and Falsworth nodded at them to follow her and strode off at a fast clip, Lieutenant Ross at her heels.

Steve turned to follow, and Stark moved to intercept him, his right hand held out.

“Thanks for doing the heavy lifting for me, Rogers. It’s been nice meeting you.”

It sounded like he actually meant it, and Steve felt slightly guilty for the long list of unflattering things he’d thought about the man while he stood there holding the tenth giant piece of torpedo. “Likewise,” he said, and took Stark’s hand.

His fingers were long, and cooler than Steve had expected, and his palm was rough with odd little calluses. He could still feel them against his skin for a moment after he let go.

There was a small patch of gauze taped to Stark’s left palm, he noticed, as he tried not to look either directly into Stark’s eyes or down at his own hand. It tried and failed to cover an angry red burn that stretched down to the heel of his hand and around the base of his thumb. “That looks nasty,” he observed.

Stark lifted the hand and shrugged little. “Welding accident.”

“Steve,” Bucky said, nudging him with one sharp elbow, “come on.”

Steve gave Stark a last polite smile and followed his old commanding officer and his new one off the docks.

**Notes for the Chapter:**

> Jacqueline Falsworth has been aged up and promoted from her teenaged Union-Jack-sidekick role in the old Invaders comics to a position in British Intelligence.


	2. Chapter 2

Steve had left yesterday evening, and nobody would tell Bucky when he was due back. And since Bucky was stuck spending the entire day at the American embassy, on completely pointless guard duty, he couldn’t even go snooping around to find out. He could have stayed in America and guarded buildings no one was ever going to attack there.

Being part of the actual war was turning out to be amazingly boring so far. Steve had disappeared into a bunch of mysterious “briefings” for most of the past week, then vanished to who knows where on a mission that was sure to be dangerous and exciting. Lieutenant Ross and Bucky had been given temporary duty assignments under the American military attaché, who hadn’t even been told about Captain America until they’d shown up on his doorstep.

Bucky started to scratch at his neck again, stopping when the skin started to sting; the collar of his wool service coat itched. It was so new that fabric was still stiff, and the sleeves were slightly too long. Not everyone had extra-long gorilla arms.

Ambassador Winant had gone out to lunch twenty minutes ago, taking the military attaché with him. If today was like yesterday (and the day before, and the day before that), they would be back in a little under an hour. Then he’d get to salute somebody for the third time today. Exciting.

At first, standing at an official post in the embassy’s fancy lobby, with its patterned wall paper and elaborate plasterwork ceilings, Bucky had felt important. He was guarding what was practically US soil against Nazi attacks. The life and safety of the ‘Ambassador Extraordinary and Plenipotentiary to the Court of St. James's’ was in his hands. That had lasted until the end of the first day, when he went back to their quarters and heard all about what _Steve_ had been doing while he’d been watching diplomats walk in and out of the building and answering questions from people who wanted to know where and how to get visas to immigrate to the US.

The sound of a woman’s shoes against the marble floor made him straighten his spine and jerk his hand away from his collar. That was Betsy. All the other women who worked here wore heels, and their footsteps made a sharper, clackier sound.

“Private Barnes,” she said, after she’d returned his salute. “Private Avison is relieving you. Come with me.”

Was Steve back already? Would they even bother to get him just because Steve had come back? Maybe he was hurt. Or dead. Steve was used to having Bucky there with him, to watch his back, and he’d never been in real enemy territory before now.

He managed to wait until they were inside the car before he couldn’t stand it any longer. “Is Steve-“

“Private Rogers isn’t back yet,” Betsy cut in. “His team isn’t due to be extracted for another forty-eight to seventy-two hours.” She pulled out into the street, apparently unbothered by the fact that they were on the wrong side of the road, while Bucky sat in what ought to have been the driver’s seat and reminded himself that they weren’t about to crash into another car, no matter what it felt like.

“I could have driven us.” He’d bet it was actually supposed to be part of his job, when he was in a car with his superior officer. And no matter how oddly they set up the cars here, they couldn’t be harder to drive than a tank.

“I’ll keep that in mind once the army’s certified you for driving motor vehicles.” She said it the same way Sergeant Duffy would have – well, minus calling Bucky a screw-up or a kid – but coming from her it sounded teasing rather than stiff or disapproving.

It didn’t take a genius to see why Steve was sweet on her. That, and Bucky had seen her all dolled up in civilian clothes, and she had legs almost as perfect as Betty Grable’s.

After several minutes of silence, Betsy said, not taking her eyes from the road, “Several coded communiqués came in this morning from Washington. We’re taking copies of them to British intelligence, and no, you don’t have clearance to read them.”

“Do you?” Bucky asked.

“Do you have clearance, ma’am.”

“Well, do you? Ma’am?” He tried the wide-eyed look that occasionally still worked on Steve. The look that hopefully said he was too baby-faced and eager to please to be insubordinate.

Was she smiling? Yes, that was definitely a smile. He was off the hook.

“They’re above a first lieutenant’s pay grade.” Which wasn’t a ‘no,’ but he’d pushed it far enough already.

A couple of months ago, he could have told Betsy about the last movie he’d seen, or about the latest stupid thing Steve had been put on punishment duty for, or how he’d outshot half the guys at target practice even though they were the ones who were supposed to be trained for it. Or asked her if she still read _Sky Ace_ and those Weird Tales magazines Steve liked.

If he did that now, it would be ‘insubordinate.’ At least she didn’t treat him like a little boy anymore, though. The uniform was good for something.

Okay, he should probably quit while he was ahead, but you never got anywhere if you didn’t try, so, “Lieutenant, I’m worried about Steve being out there without any back up.”

“He has an entire squad of intelligence operatives with him.”

Intelligence operatives who didn’t know him, didn’t know how he fought or how the shield worked – it had taken almost a week before Bucky had gotten used to the way it bounced around, and there had been one embarrassing collision they were never going to talk about again – and who were going to put completing their mission before keeping Steve alive and in one piece. Jerks. “He’s used to working with a partner, not some bunch of English spooks. He needs somebody to watch his back. The first time some Nazi points a gun at him, he’ll probably try and reason with them.”

“I’m just a first lieutenant, Bucky. I don’t have the kind of influence it would take to get you onto Special Operation’s payroll.”

Translation: no, because the brass all think you’re just a lowly and useless enlisted grunt who doesn’t have enough chest hair and stubble and shiny officer’s bars to be important. How many other sixteen-year olds could shoot well enough to get an expert marksman badge, knew how to knife fight, and had already helped stop three Nazi sabotage rings and caught a German spy? “Come on, lieutenant, you’ve seen us in action. You know I’m not just some kid.”

“It took almost a month worth of meetings with British Security Coordination in New York before they agreed let Captain America work with them, and only because he’d been trained by Army Intelligence. If this mission goes well, maybe you can ask him to speak to them for you.”

From the way she said, she didn’t think that was too likely.

Knowing Steve, he’d probably already spoken with somebody in order to land Bucky on an endless rotation of nice, safe guard duty.

Then Betsy shifted gears and turned another corner, driving slowly down a street full of old, expensive-looking buildings. “Here we are, Private. Get the documents ready.”

London street signs seemed to operate on the principle that if you had to read a sign to know where you were, you had no business being there in the first place, and it took a moment before he found the tiny black and white plaque on the corner of one of the buildings.

“Wait, is this _the_ Baker Street? The Sherlock Holmes Baker Street?” If he’d ever really thought about it, he’d have guessed that it was a fake address, like Superman’s Metropolis or the Hardy Boys living in some imaginary small town in New York. 

And she was parking in front of No. 64. Which meant 221b Baker Street was probably only a few blocks away. Well, okay, at least ten blocks, but they had a car. Maybe they’d drive past it on their way back to the consulate.

He could guard things no one was going to attack back in America, but they didn’t have Sherlock Holmes’s house in America.

The two of them were stopped inside the front door by a bored-looking guard who asked to see Betsy’s orders. Bucky gave him a commiserating look as he waved them in.

Handing over the papers took less time than he’d expected and was less exciting than he’d hoped. They didn’t pass any rooms full of secret equipment or exotic foreign spies or anything; it was a lot like the consulate, just with more people in British uniforms.

There were more British uniforms in the front entrance when he and Betsy signed out with the guard, and one lone guy in snappy civilian clothes who looked familiar. It wasn’t until he said something to the guard and Bucky heard his voice – American, with no accent – that he recognized him.

“Mr. Stark. What are you doing here?”

Mr. Stark swung around when he heard his name, looking mildly surprised. For half a second, Bucky could almost see him thinking ‘Where the hell do I know this kid from?’ before his eyes went to Bucky and Betsy’s uniforms and the penny dropped. “We met at the docks the other day, didn’t we?”

Betsy nodded. “Lieutenant Ross,” she said, introducing herself again. “I’m surprised you remember us.”

“There aren’t that many Americans in London these days, let alone pretty ones.” Mr. Stark turned to Bucky, then, finally answering his question. “I’m doing some work for the Inter-Service Research Bureau. Private Barnes, right? How do you like London?” 

He’d remembered Bucky’s name. It was probably silly to feel flattered, but important people tended not to notice him now that he was just a lowly enlisted man, especially when he was standing next to pretty - and higher ranking - Betsy and with Steve towering over him in all his ginormous tallness. “I haven’t really seen any of it yet,” Bucky said, which was true. The drive here had been the closest thing to sight-seeing he’d done so far.

“You can’t come to London and not sample the nightlife. Give me a call some evening when you’re free. I’d consider it a patriotic duty to show our boys and girls,” he smiled at Betsy, “in uniform what you’ve been missing. Bring your friend from the dockyard. I owe him a drink or two after the other day.”

“Really?” Tony Stark, the millionaire businessman, wanted them to come have a drink with him? There really were advantages to being in uniform. Especially when you looked as good in it as Betsy did, because Stark obviously intended the invitation mostly for her.

“Really.” Mr. Stark grinned, displaying perfect, even white teeth. “Like I said, it’s practically a service to the country.”

If putting the moves on Betsy was a service to the country, anyway. Betsy, of course, saw straight through his act. “Thank you for the invitation, Mr. Stark,” she said coolly.

“Please, call me Tony. And remember, tell Private Rogers he’s invited, too.”

“ _Please,”_ Bucky mimicked, once they were back in the car. “ _Call me Tony._ We’re taking him up on it, right?”

“I’ll think about it. It isn’t every day a girl gets asked out to dinner and drinks with a millionaire.”

She sounded almost flattered. Something else for Steve to be jealous about when he got back.

Steve ought to have made a move on Betsy while they were still back in the states. He wasn’t going to have a prayer now.

***

“And you’re certain this device was exactly as you’ve described it?”

“Yes, Sir, Colonel.” The second voice was American, with a familiar hint of New York City to it.

Both voices cut off as Tony stepped into the room, and a half-dozen people all turned to stare at him, including Major Falsworth. Five of them were in uniform, most of them high ranking, and the sixth…

The dull blue and red leather molded so closely to his body that every angle of bone and curve of muscle was outlined. His pants might as well have been painted on, and the bulge they completely failed to conceal was so distracting that it took Tony a moment to realize that the man’s blue leather jacket had red and white stripes down the torso, and a white star in the center of his broad chest. It was as if a Grand Prix driver had decided to make his racing leathers out of the American flag.

His leather helmet and partial face-mask had little wings on the side. It was a bizarrely whimsical detail.

“I thought I’d better fetch Mr. Stark before we got into the technical details,” Major Crandall said. He didn’t mention that he’d pulled Tony out of a test run with a newly refined version of Nobel’s plastic explosive without bothering to tell him what they needed his ‘expert opinion’ on.

If he had, Tony would have come running. Forget Lewes bombs and timing pencils; he could play with them any time. The US government’s most secret military experiment – well, most secret if you ignored whatever Bruce was doing out in New Mexico – was standing right here in front of him. He’d heard rumors about the project, of course, but if he’d expected anything, it wasn’t this. He’d expected something more, or maybe less, than human.

He was tall, maybe even a little taller than Tony, with the muscles of a Greek god, but he looked like an ordinary man. A very attractive ordinary man, but still just a man. And a younger man than Tony had envisioned, all things considered. 

“Captain America, I presume,” Tony said. “I thought you were just a rumor.”

“A little more than just a rumor,” Captain America said. His voice sounded odd, as if he were forcing himself to speak in a lower register than he normally did. “Most of it’s classified.”

“The rumors don’t do you justice,” Tony told him, with his best smile.

Were his ears actually turning red? That was adorable. Where had they found this kid?

Assuming they had found him and not just grown him in a vat. No, that was too out there even for what he’d heard about the Super Soldier Project.

“Tell Stark about the device you saw, Captain,” one of the officers said. His shoulder boards marked him as a colonel. “From the beginning.”

Captain America’s back straightened slightly. “We found it inside the plant while we were looking for the equipment for manufacturing heavy water. Like Captain Braddock said, the information from your agents in France was wrong. They weren’t making heavy water there. One of the French resistance men we met up with was a physicist; he said the entire plant set up was all wrong for that. He couldn’t tell us what the equipment was actually for; he said he’d never seen anything like it.”

“That’s what we brought you in for, Stark,” the colonel said. “We need you to confirm for us if what Braddock’s team discovered is harmless, or some kind of new Nazi weapon.”

“What could Doctor… what was his name? Anyway, what could he tell you about it?”

“Dr. Lieber.”

“Leopold Lieber?” Damn. Reed had been friendly with him. No one in the field had heard anything from him in over a year; now they knew why. “He’s a physical chemist, actually, not a physicist. He did some of the pioneering research on the autodissociation of heavy water, so if anyone should know, it’s him.”

“He said there was no identifiable power source. And it gave off traces of a form of radiation he couldn’t identify.”

No wonder Special Operations was concerned enough to drag Tony into this, despite their usual uneasiness at letting an American civilian have too much access to top secret and ultra-secret information. Radioactive material meant something that might be usable in nuclear fission, and while Germany might have lost some of their top physicists to the US, they still had some of the best scientists in the world working for them, and access to an increasing number of resources. The American nuclear program’s main advantage, besides having Bruce Banner and Reed Richards, was the plutonium and uranium deposits in the southwest, and the fact that Nazi Germany didn’t have access to anything similar.

“It was about the size of this room,” Captain America went on, “and it had- Look, give me a piece of paper and a pencil and I can draw it for you. It’ll probably be more accurate than any description I can come up with.”

Major Falsworth handed him a stub of pencil and several sheets of paper, and he sat down at the conference table that dominated the center of the room and began to sketch.

He wasn’t a trained draftsman – he didn’t use a ruler or a T-square, and as a result, his lines weren’t exactly straight and the entire drawing couldn’t have been to scale – but what Tony could see of the drawing over his shoulder was surprisingly good, better than he’d expected from someone who wasn’t an engineer. It was detailed, with shadows shaded in and the spots where the light hit various surfaces highlighted.

It wasn’t until he stopped looking at the artistic flourishes and started looking at the picture as a whole that parts of the device became recognizable. Not the design itself, but the blend of seemingly random superstitious ‘magical’ symbols and equipment intended for generating high energy electromagnetic fields.

The Mandarin’s first crude attempts to master the alien technology he’d discovered had looked something like this, with Chinese characters inscribed all over the equipment instead of Norse runes. He’d used the ‘magical’ symbols as window dressing, to convince first his followers and opposing crime lords and then the Japanese that he had supernatural powers.

Like the Mandarin's devices - like Tony's armor when his chest device was removed - this one had no visible power source. The Mandarin had used the alien ‘rings’ he’d found to power everything he’d built. Had the Germans uncovered another crash site?

No, from what Gene had told Tony, the few records from the spacecraft that his father had been able to translate had said that there were only ten rings. The Mandarin had found the first five at the crash site, still undisturbed by the Han dynasty sages who’d originally explored it, and Gene had found the others in that underground tomb complex. This thing, whatever it was, was intended to be powered by something else.

“Had anything been removed from the site before you got there?” Tony asked.

Captain America’s head jerked up, the back of his skull nearly colliding with Tony’s chin.

“Mr. Stark. I didn’t hear you come up behind me.”

“Sorry. Dad always did tell me it was rude to look over people’s shoulders.” He leaned over Captain America and tapped one of the sequences of runes that decorated the equipment. “Are those an exact reproduction of what was on there, or an approximation?”

Captain America leaned his head sideways a fraction, away from Tony’s arm. “Both. I can remember where they were, but not what most of them actually looked like. Just that it was some sort of runic alphabet.”

Major Falsworth titled her head sideways, trying to get a look at the picture despite the fact that it was upside-down from her angle. “Any ideas, Mr. Stark?”

“It’s either some kind of half-baked attempt to fuse science and Germanic mysticism, or it’s pretending to be. Had anything been removed from the room?” He looked back down at Captain America as he asked the question. From this angle, he could see the stitching on his leather cowl, as well as an almost invisible prickle of blond stubble along his jaw. He hadn’t come here straight from the field – the leather costume was too clean for that – but he hadn’t stopped to shave along the way. Someone must think this was urgent, despite how silly the pseudo-mysticism slapped all over what they’d found looked.

Captain America looked back down at his drawing for a moment, rubbing at the back of his neck as he thought about that. “I don’t know. We set the charges and then got out of there as fast as we could. There wasn’t much time to look around.”

Tony looked back at the drawing again, reevaluating it. “That’s pretty good for a drawing from memory of something you didn’t have much time to study.” And now that he looked at it again, there was something else familiar about the equipment, something beyond the mishmash of science and superstition. The fact that he couldn’t place it was going to nag at him for days.

Captain America shrugged, and gave Tony a sort of ‘aw shucks’ grin that should not have been as drenched in sex appeal as it was. “Two years of art school before the army got ahold of me.”

Well, there went the grown in a vat theory, not that he’d actually believed it to begin with. It wasn’t the kind of past he’d have expected the army’s ultimate human weapon to have, either, if he’d sat down and thought about ‘the Super Soldier’ having a past at all.

“Anything else you can tell us about the thing, Stark?”

Tony didn’t actually jump, but it was a near thing. Between the tantalizingly almost-recognizable technology and the fact that he was inches away from the most attractive man he’d met in months, who was dressed head-to-foot in tight leather and smiling at him, he’d almost forgotten about that he had an audience.

One of the men standing against the far wall – a tall, balding man in a conservatively cut suit with no visible military insignia – gave him a thin smile. “I think what Colonel Ridley would like to know is, is it dangerous? In the event that this wasn’t an isolated project, is it something that we need to worry about?”

Tony straightened, so that he was no longer practically breathing on the back of Captain America’s leather-clad neck, and offered him a shrug. “Whatever it does, it’s designed to use a whole lot of power while it’s doing it. If nothing else, it would probably make a spectacular explosion if it overheated. And giving off radiation readings…” he let the rest of the sentence go unsaid; everyone there would know what that might mean. “I wish I knew what they were using as a power source, but they must have moved it before your team got there.”

Everyone was still staring at him expectantly, including Captain America and Major Falsworth.

“It’s high energy equipment, it’s complicated and unusual, and given the possible presence of radioactive material, they might be trying to somehow split the atom with it, so yes, I think whatever it is, we want Hitler to not have a working model of it.” Then, because he couldn’t help it, “And if your boys find anything else like it, please tell me about it. Now you’ve got me curious.”

“Thank you, Mr. Stark,” Colonel Ridley said. “You’ve been quite helpful.”

And just like that, the meeting was over. Tony’s portion of it, anyway. He spent the rest of the afternoon back in the lab he’d started out in, playing with nice, only moderately secret blasting jelly, then was driven back to Bletchley Park to work on decoding more wireless transmissions that were carefully removed from all context.

If he’d wanted to, he could have easily worked out what at least some of them had come from, and what they meant, but Enigma machines were familiar now, and thus nowhere near as intriguing as whatever had been in that French power plant.

***

“It’s in the basement?” It was silly to feel disappointed, Steve knew, but when he’d pictured London’s jazz clubs, he hadn’t envisioned going down a flight of – admittedly luxurious – stairs and into a hotel basement. The carpet underfoot, satin wallpaper, and sleek wooden stair rail were fancier than anything he’d seen on his way into the old former speakeasies this resembled, but it was still a basement.

“It used to be in the grand ballroom upstairs, but they moved everything down here during the Blitz.” Stark shrugged one shoulder. “I would have taken you to Café de Paris, but it blew up a couple weeks ago.”

“Really?” Bucky asked, fascination in his voice, and then, in a slightly less ghoulish tone, “Was anyone hurt?”

“Two mines exploded right in the middle of the dance floor. One of the band leaders was killed.” The words were soft, more serious than anything Steve had heard from Stark when he wasn’t focused on Nazi technology. Then he smiled, a quick flash of perfect teeth, and waved a hand at the door at the foot of the stairs, stepping aside to let Betsy go first. “After you, Lieutenant. We’re here to have a good time, not talk about bombings.”

Betsy smiled up at him, the kind of flirtatious smile she’d only given Steve in his imagination; Steve looked away, but he didn’t have to see them to know how perfect a picture they made, both tall and dark-haired, Betsy with her red and white polka-dotted skirt swirling around her calves and Stark in his stylish black suit that cost more than Steve earned in a month.

Stark followed her down the stairs, Steve and Bucky trailing behind him.

A basement, it turned out, wasn’t always just a basement. This one was large and well lit, with plush red carpet surrounding a wooden dance floor, a long, mirrored bar along the side of the room, and a small band shell in the back corner. A crystal chandelier hung from the ceiling, glittering like something out of a movie.

The room was full of men in uniform, most of them RAF and Royal Navy, and women in heels and brightly colored dresses. On stage, a short, balding man was crooning into a microphone, his voice a smooth tenor that was completely at odds with his nondescript appearance.

Stark selected a table for them, pulled out a chair for Betsy, and asked what everyone wanted to drink. “On me,” he said. “It’s the least I can do for our brave soldiers.”

“A martini. Or anything really, I’m not picky.”

Stark grinned. “A woman after my own heart.”

“I’ll have a beer,” Steve said, “and he,” he jerked a thumb at Bucky,” will have a club soda.”

“I’m old enough to drink here,” Bucky protested.

Stark was back almost before Bucky had finished complaining about the unfairness inherent in treating him like the kid he was. He handed Betsy her drink with a smile and a theatrical flourish, set another martini down at his own place, and handed Steve his beer, which left two drinks remaining on the fancy little tray.

Stark set the second beer down in front of Bucky, along with the club soda Steve had ordered him. “If you’re old enough to wear a uniform and fight for your country, you’re old enough for me to buy you a drink.”

“He’s _sixteen_ ,” Steve said.

“I’d been in half the speakeasies in New York at his age,” Stark said, grinning across the table at Steve, “and it didn’t hurt me.”

That would explain why the news stories about Stark’s love of the city’s nightlife went so far back, despite the fact that he couldn’t be much older than Steve. The moustache and that casual air of self-confidence made him seem older, but if Steve remembered right, he’d been born after the Great War ended, which made him twenty-two or twenty-three at most.

“We’re a long way from New York here,” Betsy said. The look she was giving Steve from under her eyelashes was a clear reminder to play nice. “What kind of work are you doing for the British, Mr. Stark? I thought you’d be leaving us as soon as the shipment was taken care of.”

“It’s Tony, and it’s classified.”

If Stark thought that was going to impress Betsy – Lieutenant Ross, he reminded himself, but it was hard to keep thinking of her that way when she was out of uniform – then he was barking up the wrong tree. She had access to the kind of top secret information a civilian like Stark would never have clearance to get within ten feet of, even one involved with British Intelligence the way Stark seemed to be.

“I’m not just trying to sound exciting and mysterious,” Stark protested, giving the three of them a rueful little smile that looked somehow more real than those perfect, movie star grins. “It really is. I had to sign non-disclosure agreements and be sworn to secrecy and promise to swallow cyanide capsules if the Nazis ever capture me.”

He was probably exaggerating, but then again, Colonel Ridley _had_ called him into Steve’s debriefing yesterday. Whatever he was doing for the British government, it involved security clearances high enough that they trusted him with the details of SOE operations and top secret information about Nazi technology, as well as the fact of Steve’s presence and the extent of America’s covert involvement in the war.

“I’d ask what you’re doing for Uncle Sam, but I suspect I’d get the same answer.”

“Not really.” Bucky made a face. “I spend most of the day guarding the US embassy against the dangerous visa-seeking hordes. I think they have Steve shuffling papers somewhere. That’s what education gets you.” He smirked at Steve, and added, “You never should have told the army about all that art school.”

Steve had long since stopped being startled by how good Bucky was at covering for both of them; he never stumbled over a lie, no matter how bald-faced. “They had me drawing posters about the dangers of VD back in the states. Anything is better than that.”

That had been one of the more humiliating punishment duties Sergeant Duffy had assigned him, after ‘Captain America’s’ secret nighttime activities had caused him to miss one too many morning roll calls.

“Really.” Stark eyed him speculatively, and Steve felt his face heat. “Any words of advice, Doctor Rogers?”

“Stay away from women in dance halls. They’re personally recruited by Hitler to undermine the war effort by sapping the stamina of America’s fighting men.”

“Is that so?” Stark raised his eyebrows, miming surprise. “I’ll keep that in mind.” He took a long drink of his martini, his eyes fixed on Steve, and something about the weight of that lazy, blue gaze made Steve feel ridiculously self-conscious. No man should have eyelashes that long.

“Is London always like this?” Steve asked, scrambling for a topic that would get Stark’s attention off him before he embarrassed himself somehow or stared too obviously at the way Stark was licking that last drop of vodka martini off his lips. “We’d heard there were bombing raids every night.”

Bucky took a sip of his beer, made a face, and then took another, larger sip when he saw Steve looking at him. “There was one while you were out of the city. We all trooped down to the embassy basement and waited there for hours.”

“There was?” He hadn’t known that, and was almost glad for it; if he had, he would have worried about Bucky and Betsy the entire time he’d been in France. They were supposed to be safe in London.

“It wasn’t as exciting as it sounds,” Betsy said, and Steve got the distinct sense that she was trying to reassure him the way he might Bucky.

“There haven’t been as many lately.” Stark drained the remains of his drink in one long swallow, then simply held the empty glass for moment, staring down into it. “Let’s hope it stays that way. It was… bad, when I first got here.”

No one said anything for a moment, and then Bucky asked, with a brightness that almost didn’t seem forced, “Did you really go out with Rita Hayworth?”

Stark grinned. “No, but I did meet her at a party once.”

The conversation meandered from there to past girlfriends – Stark’s, mostly, since neither Steve nor Bucky had ever been lucky enough to have a steady girl and Betsy was unforthcoming on the subject of former beaux – and then to their wild youths in general. Again, mostly Stark’s.

“And of course,” Betsy was saying, gesturing with the toothpick that had held the olives in her drink, “they made me the goalie, because I was the tallest girl on the team, which wasn’t so bad in practice, but when we played our first game, I was terrified. All the other girls were running straight at me, tossing balls at my head, and all the kinds of things I’d been hearing from my uncle Thad since I was a little girl just came spilling out of my mouth. The other team’s coach said ‘her girls had never heard that kind of language in their lives.’” She said the last bit in a mock-prissy tone that made Steve suspect it was a direct quote. “And that,” she concluded, “was how I got kicked off the field hockey team.”

“Uncle Thad?” Bucky asked.

“Short for Thaddeus. He’s a lifelong army man. I used to spend the summers at his house when I was a little girl.”

“Wait, Thaddeus Ross?” Stark demanded, straightening from his slouch against the back of his chair. “You’re related to General Thaddeus Ross?” He covered his face with one hand, grimacing. “Elizabeth Ross. I should have—You’re Bruce’s fiancée, aren’t you? Can we just take my apology as already said and pretend I haven’t been flirting with you all evening?”

Bruce’s… Who the hell was Bruce? Not Betsy’s ‘fiancé,’ that was for sure, since she’d never so much as mentioned his name in the months Steve had known her. 

“What? No!” Betsy held up both hands, shaking her head. “That’s the _other_ Elizabeth Ross. She’s my cousin. We’re both named after our grandmother. ” She gave another, slower headshake. “I come all the way to England,” she said, with the air of someone speaking more to herself than anything else, “and people are still mistaking me for Betty.”

“I’m sorry?” Stark offered. ‘Betty and Betsy?’ he mouthed.

“Betty and Betsy?” Steve asked skeptically.

“I know,” Betsy said. “Believe me, I know.” She turned back to Stark. “You know Dr. Banner?”

“He’s working on some project in New Mexico with a friend of mine. Nuclear physics is a small world.”

Stark must have caught the bartender’s eye or made some oblique gesture, because almost without Steve noticing, two new martinis and a beer were deposited at their table, along with another club soda for Bucky, who still hadn’t finished his first drink. Given the faces he’d been making when he thought Steve couldn’t see, he wasn’t exactly enthusiastic about the beer Stark had bought him. Steve didn’t blame him; the beer here was stronger than it was back home, though it was harder for him to gauge that these days, and it was served room temperature.

“Betty’s the one who got me reading science fiction,” Betsy said, to Steve. “We used to smuggle terrible pulp novels and magazines into the house, like the ones where Shirley Temple solves mysteries, or about who Rudolph Valentino and Douglas Fairbanks, Jr. were dating. Once she brought home an issue of Weird Tales, and I was hooked.”

Steve reached for his second glass, reminding himself to slow down after this one. Drinking beer instead of something harder gave him a little more leeway, but if he kept drinking alcohol as if it were soda, then at some point in the evening, Stark was going to notice. “I think I just always read that kind of thing. My mom used to read me stories from those fairy tale books with the brightly colored covers. The Blue Fairy Book, the Red Fairy Book, things like that.”

Bucky wrinkled his nose. “There’s reading pulp science fiction stuff because it has mostly naked dames on the cover, and then there’s reading something called a fairy book.”

Steve reached out and cuffed him lightly on the back of the head. “There’s a lady present, champ.” Sometimes, he could almost forget how young Bucky was, and other times, it was very obvious. 

Fairy books. If only he knew. No, scratch that. It was a minor blessing that he didn’t, given the amount of trouble that could land Steve in.

“So,” Stark said, ignoring the byplay, “have you read that Asimov story in the latest Amazing Science Fiction? It’s pretty good, even if he does throw around words like positronic and pretend they actually mean something.” He gave a dismissive flick of his fingers. “You could never actually get a computer to follow vaguely defined rules like ‘never harm a human,’ but it’s nice to see someone put some thought into the ways computers function differently than a human brain.”

That was missing the point entirely, and Steve said so. “The point is the ethical dilemma it causes for the robot in situations where the laws conflict with each other, not whether or not it would actually work.” He waved the idea away. “What could a robot do to keep one human from attacking another human, can you truly protect someone without using violence against their attackers, you know, that kind of thing?”

“The robot would do exactly what it does in the story.” Betsy was leaning forward now, animated in a way she hadn’t been when Stark had been flirting with her (or, unfortunately, when Steve tried to flirt with her). “It would grind to a screeching halt and stand there frozen, because it couldn’t obey one of the laws without breaking another.” 

Stark held up one long finger. “Unless it rewrote its own code.”

“Could it do that?” Bucky asked, sounding grudgingly interested.

“Not if whoever designed it was smart,” Stark said, as if it were obvious. “But a computer powerful enough to handle those kind of calculations would be the size of this building.” He gestured expansively, indicating something huge. “We’ve had some success at SI with point-contact transistors, but even with those, it would be next to impossible to make something small enough that it could walk around under its own power. A stationary computer, though, or bank of interconnected computers… one of the scientists I worked with when I was still in college had this idea that you could create a system of linked computers that each performed a specialized function, like ants in an ant colony, and have them mimic a living organism. And there’s synthezoid technology, of course, but that’s more medicine than engineering.”

He didn’t bother to explain what a synthezoid was, or a transistor, apparently assuming that they all already knew. That, or just not caring.

Stark’s eyes lit up when he talked about linked computers and integrated circuits and transistors and vacuum tubes, the same way they had when he’d been elbow deep inside a torpedo, or hanging over Steve’s shoulder to stare at his sketch of the Nazi mystery machine.

Bucky was fiddling with his half-finished beer, shifting the glass around to leave overlapping circles of condensation on the table. “Are you sure they couldn’t have built one already?” he asked. “The other guys at the embassy say there’s one in the city. It’s supposed to help get people out of buildings after bombings, like a robot air raid warden or something.”

Stark shrugged. “If it actually exists, it’s either a firefighter in some kind of protective gear, or a wind-up automaton. It would be a lot easier to build a robot that could perform a single action over and over than something that can think for itself.” He shook his head, and tossed back the rest of his drink, holding the empty glass up to signal the waiter to bring him another. “People think they see all sorts of things during air raids. It’s dark, it’s loud, and last time there was a really bad one, half the city was on fire.”

And then, as if Stark had jinxed them, the soft susurrus of the crowd was cut through by a wailing klaxon.

He didn’t have to ask Stark what it meant.

Around the room, people leapt to their feet, and there was a sharp crash as someone knocked a glass over.

The band leader stepped up to the microphone and said, with forced cheer, “Sounds like Goering’s boys are back for their nightly visit. We’re going to keep playing, ladies and gentlemen, so sit tight, make room for everyone coming down from upstairs, and remember not to go back up until they’ve sounded the all-clear.”

He was standing, he realized, his hands groping for the shield he wasn’t wearing, the sidearm he wasn’t carrying. There was no way to carry the shield with him subtly, and… what exactly would he do with it in this situation, anyway?

People, presumably hotel guests and staff, were spilling into the room. A woman in a fur evening wrap, a boy in a doorman’s uniform who looked scarcely older than Bucky, a group of men in suits, a man and a woman, each of them holding a small, sleepy-looking child.

Steve stepped away from the table, waving an elderly man toward his seat. The others were on their feet as well, and Betsy was gesturing toward the young family, offering them the rest of the seats at their table.

They would be safe down here, presumably, but outside…

He stared down at his hands, one of his knuckles still red and slightly puffy from where he’d punched a German soldier in the face in Norway. People were probably dying, or would be before the air raid was over, and there was nothing Steve could do about it.

“We should move to the back of the room,” he said, looking back up, “to make space. How long do these usually last, Stark?”

There was no answer. Stark was nowhere in sight.

***

This was a bad idea, Tony knew. Rogers and Ross were bound to notice his disappearance, and he would have no good way to explain it. By the time he’d climbed the steps and crossed the hotel lobby, he knew he’d made a mistake, but it was too late to turn back now.

And how would he justify doing so to himself, anyway? He was in the middle of London, with German planes overhead and German bombs falling, not miles away in Buckinghamshire; sitting safely down in the cellar-turned-nightclub and pretending his briefcase held papers or a change of clothes instead of an experimental lightweight armor prototype would be inexcusable. 

It was pitch black outside, except for the dim glow of searchlights overhead, but he’d had practice by now at putting on his armor by touch. Locking the seals that held the pieces of the armor together, connecting the breastplate to the battery in his chest device, all of it was as automatic as breathing. This version went on faster than his real armor, since it was really just a helmet, breastplate, boot, and gauntlets connected by thin sleeves of fine wire mesh. He’d traded any real form of protection for the ability to carry the disassembled pieces around with him, which meant he’d better not get shot. Bullets wouldn’t bounce off this one, and he’d have a hard time explaining his absence to his companions if he came back shot half to death.

It was going to be hard enough anyway. Ross was an intelligence agent, regardless of what her official position with the army was. She wasn’t going to buy some half-baked excuse about slipping off to find the WC or getting lost in the crowd. And Rogers… How many tall, stunningly well-built blond American soldiers who’d been to art school could there be in London? He wasn’t going to be easily convinced by a lie, either.

He’d deal with that later. He’d always been good at thinking on his feet. Right now, Iron Man had a job to do.

It took only a few moments after he reached the street to realize that something was wrong. With cars shut down, lights shut off, and half the population of London seeking shelter underground, the city was eerily silent.

That wasn’t right. By now, he ought to be able to hear the drone of approaching aircraft overhead. Instead, there was nothing but a distant murmur of voices as people swarmed toward the underground station one street over.

Tony stood still, straining his ears, and was just considering taking his helmet off in order to listen without its obstruction when he finally heard engine noise. It was faint, but gradually coming closer, and the timing was too slow for an aircraft propeller. He could make out individual beats, surely that wasn’t…

It shouldn’t be getting louder this quickly, Tony thought, not with such a low engine RPM, and then his stomach lurched as he recognized it.

A pulse jet.

He was listening to an actual, honest-to-god jet-propelled aircraft. That was incredible. How did they- SI was still struggling with the low efficiency and slow response to throttle input of the centrifugal-flow turbojet engine he had in development, and with aerodynamics problems with the prototype airframe’s wings, and the axial-flow engine that was going to fix those efficiency problems was… technically not even on the drawing board yet, because he’d forgotten to send the plans to Pepper. Messerschmitt and Junkers were supposed to be months behind them, maybe years, and the rumors he’d heard had all been about turbojet projects, not pulse jets. Had they settled for a more inefficient form of combustion in order to cut development time?

He’d fired his own boot jets before he had a chance to think better of it. He had to see this, whatever it was.

Saving civilians would have to wait. The RAF could handle German bombers or fighters, but this new, unknown aircraft was something different.

Tony took off, swerving to avoid first a searchlight and then a barrage balloon, climbing until he hit several hundred feet, the city a swath of blackness below him. Only the river was clearly visible, its surface glittering faintly with reflected light.

He heard the aircraft before he saw it, a faint, moving shadow against the darker blackness of the sky. It seemed too small to be as close as it sounded, the shape not quite right for an airplane.

The sound cut off abruptly, to be replaced by a familiar high-pitched whistle as the thing started to fall.

Not an aircraft; a ballistic missile. He started to dive towards it, then pulled himself up short. There was no way he’d be able to intercept a falling bomb, not from this far away. And already, he could hear more of them.

When the first missile hit, the explosion was spectacular even from across the river and three hundred feet up. The fireball bloomed against the dark, bigger than three normal bombs, and the dull boom of the explosion hit him a fraction of a second later.

Tony was flying toward the closest source of jet engine noise before he had a chance to think about it. _’I could divert it_ ,’ he thought, _’into the river, maybe, or the ground outside the city._

It would be a calculated gamble, and one that might still end up costing lives; nowhere in the immediate vicinity of London would be completely free of people. On the other hand, if he could get close enough and aim for the right part of the missile…

The first repulsor blast missed by nearly a foot. The second took out the flying bomb’s engine and fuel tank, and the explosion that followed ignited the explosives inside.

There was a dizzying rush of color and sound as the shock wave hit him like a slap, and Tony went tumbling backwards through the sky. For a long, sickening moment, he didn’t know which way was up.

A building was rushing at him, and Tony pulled up sharply enough that G forces wrenched at his stomach and blackness narrowed the edges of his vision. He was briefly thankful that he’d just had drinks with Rogers and the others, not dinner, and then the sound of more missiles penetrated the ringing in his ears.

He drew in a deep breath, sucking air back into lungs jarred by the explosion, and flew toward it.

**Notes for the Chapter:**

> For those who care as deeply about the difference between pulsejet and turbojet engines as Tony does, here's a highly over-simplified explanation: 
> 
> A standard turbojet jet engine works via forcing super-heated compressed air through a turbine, which creates a continuous high-speed “jet” of air out of the back of the engine and pushes the aircraft forward. “Centrifugal-flow” and “axial-flow” refer to the path the air takes as it goes through the compressor at the front of the engine (axial compressors are more complicated, but work better in aircraft engines for a variety of technical reasons). Air is sucked into the compressor, flows into a combustion chamber where it’s mixed with fuel and set on fire, and then forced out the back through the turbine. Both the compressor in the front and the turbine in the back contain approximately a zillion moving parts. The US, the UK, and Nazi Germany were all working on various forms of turbojet aircraft in the late 1930s/early 1940s, but none of them were fully operational before 1944. 
> 
> A pulsejet, famously used during WWII used to propel the German V-1 Flying Bomb, is a much simpler form of jet engine that skips the turbine and compressor in favor of just dumping a bunch of fuel into a combustion chamber, mixing it with air to make it explosive, and igniting it. The explosion forces hot air out of the back of the engine. Instead of an air compressor forcing air into it, a pulse jet has a set of simple valves at the front that open and close repeatedly. The valves close when an explosion goes off, then open again to suck air into the now-mostly-empty chamber where it’s mixed with fuel again for another explosion. And repeat (and repeat, and repeat). The series of repeated explosions happening very close together creates what Elliot Spencer would probably describe as “a highly distinctive sound.”


End file.
